JP2011120167A - Communication system and communication method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a communication system and communication method where communication efficiency is improved by allowing a system configuration to be flexibly changed. <P>SOLUTION: The communication system where a master ECU 1 and slave input/output devices 2a, 2b, 2c, 2d are ring or daisy chain connected is achieved by: allowing the master ECU1 to transmit address and data setting information to an input/output device 2a being a slave device; allowing the input/output device 2a to not only rewrite the address information while determining address thereof from the address information but also write the setting of the data used thereby in the data setting information so as to transfer the written data setting information to the adjacent input/output device 2b; further allowing the address and data setting information to be rewritten and written by each device in the input/output devices 2b, 2c, 2d so as to be transferred to the master ECU 1; and finally allowing the master ECU 1 to receive the transferred information so that the entire system configuration is confirmed for the start of the communication. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a communication system including a plurality of communication devices, in particular, the configuration can be made the same without giving unique identification information to each communication device, and moreover, the system configuration can be flexibly dealt with, The present invention relates to a communication system and a communication method that can improve communication efficiency.

  In recent years, control systems that control a large number of devices and realize various functions as a whole have become widespread. A control device for controlling each device is connected to each device, and each control device is provided with a communication means to exchange data with each other so that each control device does not perform independent control, but other control devices, etc. It is realized as a communication system that executes control in cooperation, such as controlling a device to be controlled corresponding to itself based on data obtained through the network, and is used in various fields.

  In such a system, as the function increases, the number of devices to be controlled increases, and the number of devices such as sensors that acquire or measure data used for control also increases. Especially in the field of vehicles, a lot of devices such as actuators or sensors corresponding to various functions are arranged in the vehicle, and an ECU (Electronic Control Unit) is arranged corresponding to each as a control device for controlling each device. Operates by sending and receiving data to and from each other.

  In a communication system in which a large number of control devices each have a communication function and cooperate as a communication device, unique identification information is set in advance and stored in its own memory, and when each communication device transmits data, It has been configured to transmit identification information. Thereby, when each communication device transmits data, it transmits both its own identification information stored as the transmission source and the identification information of the destination device. Thus, each device can determine whether or not there is data addressed to itself, and can recognize the identification information of the device that is the data transmission source.

  However, in the conventional method, it takes time to set and store unique identification information in advance. In addition, when a large amount of control devices are required, unique identification information must be set for each, and the information amount of the identification information becomes enormous.

  Therefore, in Patent Document 1, a plurality of communication devices connected in a ring type or daisy chain type connection form can specify mutual addresses without setting their own identification information. The invention is disclosed. In this invention, a plurality of communication devices are composed of one master and a plurality of slaves. When the master transmits an arbitrary address value X, each slave adds a fixed value to the address value X and transfers it. As a result, each device recognizes the received address value or the address value to be transmitted as its own address value. Also, the master can recognize the number of slaves based on the address value after being transmitted to all devices. Thereby, even if the identification information is not set in advance, the plurality of communication devices can recognize each other. Therefore, the communication device can be manufactured with the same configuration, and is suitable for mass production.

Japanese Patent Laid-Open No. 3-72740

  According to the invention disclosed in Patent Document 1, connection processing or data transmission / reception is sequentially performed in a state after each communication device is actually connected to a communication line without setting unique identification information in advance. By performing the processing, identification information corresponding to the connection order from the master can be given to each communication device, and can be used during communication.

  However, after adding identification information corresponding to the connection order from the master to each slave, it is necessary to add identification information again when it is necessary to add more slaves or replace any of the slaves. is there. In addition, after giving identification information to each communication device, the master will transmit to each slave one by one with a combination of the identification information and data of the destination slave, and communication efficiency may be insufficient. .

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a communication system and a communication method that can flexibly cope with a change in system configuration and improve communication efficiency.

  The communication system according to the first invention is a communication system in which one master communication device and a plurality of slave communication devices communicate by ring connection or daisy chain connection, wherein the master communication device includes address information of each slave communication device, And means for transmitting data setting information set to determine data used by each slave communication device; and means for receiving the address information and data setting information transferred from any of the plurality of slave communication devices Each of the plurality of slave communication devices receives means for receiving the address information and data setting information from one of the adjacent communication devices, means for determining and storing its own address based on the received address information, and A means for rewriting the received address information based on a calculation result using the address information; Means for setting information for determining data used by itself in the received data setting information, and means for transferring the address information after rewriting and the data setting information after setting to the other of the adjacent communication devices. It is characterized by that.

  In the communication system according to a second aspect of the present invention, the master communication device includes means for transmitting a data frame including a plurality of data used by each slave communication device based on the received data setting information. Receiving data from the data frame based on the setting or transmitting data to a corresponding position in the data frame based on the setting.

  A communication system according to a third aspect of the present invention is a communication system in which one master communication device and a plurality of slave communication devices are connected in a ring connection or daisy chain to transmit and receive digital signals, and each of the master communication devices comprises a plurality of bits. Means for transmitting a setting signal including an address value bit and a data setting bit, and means for receiving the setting signal transferred from the slave communication device, wherein each of the plurality of slave communication devices is one of adjacent communication devices. Means for receiving the setting signal from, means for reading an address value from an address value bit in the received setting signal, means for determining and storing an address based on the read address value, and the address value and a predetermined value Based on the calculation result, the address value bits in the received setting signal are rewritten. And rewriting means for rewriting one or more bits used by itself among the data setting bits of the received setting signal, and the setting signal including the rewritten address value bit and data setting bit to the other of the adjacent communication devices. And means for transferring.

  In the communication system according to a fourth aspect of the present invention, the data setting rewriting means includes a means for specifying a head position of one or a plurality of bits used by itself among data setting bits of the received setting signal, and a specified head position. And means for inverting the number of bits used by itself from the stored head position among the data setting bits.

  In the communication system according to a fifth aspect of the present invention, the master communication device includes means for transmitting a data signal composed of bits used by each slave communication device based on the received setting signal, and each slave communication device includes the data A bit used by itself is extracted from a signal based on a stored head position, or data is written to a bit used by the head from the head position and transmitted.

  A communication method according to a sixth aspect of the present invention is a communication method in which one master communication device and a plurality of slave communication devices communicate with each other by ring connection or daisy chain connection, wherein the master communication device includes address information of each slave communication device, And data setting information set to determine data used by each slave communication device, and each of the plurality of slave communication devices receives the setting information from one of the adjacent communication devices, and receives the received address information. Based on the calculation result using the address information, the received address information is rewritten, and the received data setting information is set with information for determining the data used by the self-address. The address information and post-setting data setting information to the other of the adjacent communication devices, and the master communication device Receiving the address information and data setting information transferred from one of the adjacent slave communication devices, and controlling transmission / reception of data by each slave communication device based on the received address information and data setting information .

  A communication method according to a seventh aspect of the present invention is a communication method in which one master communication device and a plurality of slave communication devices are connected in a ring connection or daisy chain to transmit and receive a digital signal. Each of the master communication devices comprises a plurality of bits. A setting signal including an address value bit and a data setting bit is transmitted, and each of the plurality of slave communication devices receives the setting signal from one of the adjacent communication devices, and addresses from the address value bits in the received setting signal. Read the value, determine the address based on the read address value, rewrite the address value bit in the received setting signal based on the calculation result of the address value and a predetermined value, and the data setting bit of the received setting signal Among them, one or more bits used by itself are rewritten, and the address value bits after rewriting and A setting signal including a data setting bit is transferred to the other of the adjacent communication devices, the master communication device receives the setting signal transferred from one of the adjacent slave communication devices, and based on the received setting signal, Controlling transmission / reception of data by the slave communication device.

In the present invention, the master communication device and the plurality of slave communication devices are ring-connected or daisy-chain connected, and communication is controlled by the master communication device. First, the master communication device transmits setting information including address value information of each slave communication device and data setting information set by each slave communication device. The setting information is received in order from the slave communication device adjacent to the master communication device, the address value is read from the address value information included in the received setting information, and the own address is determined based on the read address value. Receive data based on address. Further, the slave communication device performs an operation with a predetermined value on the address value of the address value information included in the received setting information, and rewrites the address value information included in the received setting information based on the calculation result. . In addition, the slave communication device sets information for determining data used by itself in the data setting information included in the received setting information, and sets data to be used based on the setting from information transmitted thereafter. Determine. Each slave communication device transfers the rewritten address value information and setting information including the set data setting information to another adjacent communication device.
Since the setting information changes from one slave communication device to another, the address value information included in the setting information is updated by the calculation result for the address value of each slave communication device, and each slave communication device uses the data setting information. Information for determining data is set. The setting information after being transferred repeatedly is received again by the master communication device, and the information of each slave communication device can be acquired from the updated address value information and data setting information included in the received setting information.
As a result, the master communication device can grasp the configuration of the entire communication system based on the setting information after transfer and control communication. In addition, each slave communication device can determine data used by itself even after the configuration of the communication system is changed, regardless of the connection order.

In the present invention, the master communication device further transmits a data frame in which the data transmitted or received by each slave communication device is collected to each slave communication device based on the received setting information after transfer. Since each slave communication device has already set information for determining data used by itself in the data frame, the slave communication device extracts necessary data based on the setting or transmits it in the frame.
As a result, it is not necessary for each slave communication device to transmit and receive data at a pair of data destination address and data at the time of data transmission / reception, and each slave communication device is transmitted at a time by ring connection or daisy chain connection. It is possible to receive or transmit the necessary data from the data frames transmitted from time to time.

In the present invention, a setting signal including an address value bit including a plurality of bits indicating an address value as address value information and a data setting bit including a plurality of bits as data setting information is transmitted from the master communication device. In order from the slave communication device adjacent to the master communication device, each slave communication device receives the setting signal, reads the address value from the address value bits in the setting signal, determines the address value, and further, the address value of the setting signal The bit is rewritten based on the calculation result of the address value and the predetermined value. Further, the slave communication device rewrites one or a plurality of bits used by itself among the data setting bits in the received setting information. Since each slave communication device rewrites the bit used by itself, the slave communication device that receives the setting signal later uses a bit that has not been rewritten. Then, the slave communication device transfers the setting signal including the rewritten address value bit and the data setting bit to the adjacent slave communication device or master communication device.
Since the setting signal is rewritten by each slave communication device and changes, the address value bits and the data setting bits included in the setting signal indicate information rewritten by all the slave communication devices. The setting signal can be received again by the master communication apparatus, and the communication can be controlled by grasping the configuration of the entire communication system based on the address value bit and the data setting bit of the received setting signal.
As a result, the master communication device can grasp the configuration of the entire communication system based on the transferred setting signal and control communication. In addition, each slave communication device can determine data used by itself even after the configuration of the communication system is changed, regardless of the connection order.

  Further, in the present invention, when rewriting the bit used by the slave communication device with the data setting bit, the slave communication device first specifies the head position where the data to be used is to be set, and stores the head position. The bit used by itself is rewritten from the head position. As a result, when a signal including data is transmitted to each slave communication device thereafter, only the bit used by itself can be read from the head position. Since each slave communication device can determine one or a plurality of bits used by the slave communication device in order from the top of the data signal, the data of a plurality of destinations can be combined into one data signal.

  According to the present invention, it is not necessary to set identification information unique to each slave communication device in advance. Furthermore, by transferring one setting information between communication devices connected to the ring connection or daisy chain connection, information for determining data used by each device is set, and thereafter, based on the control of the master communication device. Even if data is sent to each slave communication device in a batch, each slave communication device can determine the data used by itself. Even if the system configuration is changed and the connection order is changed, data can be discriminated based on the setting, and it is possible to flexibly cope with it, and it is possible to transmit and receive data collectively, thereby improving communication efficiency.

It is a block diagram which shows the structure of the vehicle-mounted communication system in this Embodiment. It is a block diagram which shows the internal structure of ECU and the input / output device in the vehicle-mounted communication system of this Embodiment. It is a flowchart which shows an example of the process procedure of the initial setting which ECU which is a master in the vehicle-mounted communication system of this Embodiment performs. It is a flowchart which shows an example of the process sequence of the initial setting which the input / output device which is a slave in the vehicle-mounted communication system of this Embodiment performs. It is explanatory drawing which shows the example of the content of the initialization frame which changes between ECU which comprises the vehicle-mounted communication system of this Embodiment, and an input-output device. It is explanatory drawing which shows typically the condition where the initial setting flame | frame is transferred between ECU which comprises the vehicle-mounted communication system of this Embodiment, and an input / output device. It is explanatory drawing which shows the example of the content of the data frame transmitted / received between ECU and input / output devices in the vehicle-mounted communication system in this Embodiment.

  Hereinafter, the present invention will be specifically described with reference to the drawings showing embodiments thereof. In the following embodiment, the communication system according to the present invention is applied to an in-vehicle communication system in which a large number of actuators, sensors, and ECUs mounted on a vehicle communicate data with each other to realize various functions. An example will be described.

  FIG. 1 is a configuration diagram showing the configuration of the in-vehicle communication system in the present embodiment. The in-vehicle communication system according to the first embodiment includes an ECU 1, input / output devices 2a, 2b, 2c, 2d, and various sensors 3, 3,... Or actuators 4 connected to the input / output devices 2a, 2b, 2c, 2d. , And a communication line 5 to which the ECU 1 and the input / output devices 2a, 2b, 2c, and 2d are connected.

  As shown in FIG. 1, the ECU 1 and the input / output devices 2a, 2b, 2c, and 2d are connected in a ring shape. Note that the communication line 5 between the ECU 1 and the input / output device 2d does not exist and may be connected in a daisy chain type.

  The ECU 1 controls the operation of the actuator based on data obtained from various sensors. The input / output devices 2a, 2b, 2c, and 2d execute communication on the communication line 5 of data input / output by the sensors 3, 3,. Sensors 3, 3,... Or actuators 4, 4,... Are installed inside and outside the vehicle and operate based on control information from ECU 1 or another ECU (not shown).

  In this way, the sensors 3, 3,... Or the actuators 4, 4,... Are not directly connected to the ECU 1, but are connected to the input / output devices 2a, 2b, 2c, 2d, respectively. By adopting a configuration in which 2b, 2c, and 2d transmit and receive data to / from the ECU 1, the input / output devices 2a, 2b, 2c, and 2d collectively communicate the data with each data at an appropriate transmission / reception timing. It is possible to reduce the load on the ECU 1.

  The communication between the ECU 1 and the input / output devices 2a, 2b, 2c, and 2d is executed by a method controlled by the master based on the master / slave method, although the communication protocol is not limited. Specifically, in the first embodiment, in order to transmit / receive data input / output by the sensors 3, 3,... Or the actuators 4, 4,... Between the ECU 1 and the input / output devices 2a, 2b, 2c, 2d, The ECU 1 serves as a master, the input / output device 2a operates as a slave 1, the input / output device 2b operates as a slave 2, the input / output device 2c operates as a slave 3, and the input / output device 2d operates as a slave 4, and the ECU 1 operates as the input / output devices 2a, 2b, 2c. , 2d is controlled.

  FIG. 2 is a block diagram showing an internal configuration of the ECU 1 and the input / output device 2a in the in-vehicle communication system according to the present embodiment. Since the internal configurations of the input / output devices 2b, 2c, and 2d are the same as the internal configuration of the input / output device 2a, detailed description thereof is omitted.

  The ECU 1 includes a control unit 10, a storage unit 11, and a communication unit 12. The control unit 10 uses a CPU (core) to execute processing for controlling each of the sensors 3, 3,... Or the actuators 4, 4, ... based on a program stored in the storage unit 11. You may implement | achieve in hardware by the combination of a circuit. The storage unit 11 uses a non-volatile memory such as a flash memory, and stores a program as described above, as well as setting information referred to during control. The control unit 10 uses a RAM (Random Access Memory) (not shown), and state information input from the sensors 3, 3,... Or the actuators 4, 4,. Control information to be output to is temporarily stored.

  The communication unit 12 performs communication processing via the communication line 5 according to a predetermined protocol based on an instruction from the control unit 10. Specifically, a process of converting the control information given from the control unit 10 into a signal of a format conforming to the protocol and outputting it, or a process of extracting information from the signal received from the communication line 5 according to the protocol, etc. Do. As shown in FIG. 2, the communication unit 12 has two ports (121, 122), and distinguishes between communication with the two input / output devices 2a directly connected and communication with the input / output device 2d. Is possible.

  The input / output device 2a includes an arithmetic processing unit 20a, a communication unit 21a, a storage unit 22a, and an input / output unit 23a. The input / output device 2a is configured by an ASIC (Application Specific Integrated Circuit) in which these components are formed. An FPGA (Field Programmable Gate Array) may be used. It should be noted that the function of each component may be realized by software processing by a microcomputer.

  The arithmetic processing unit 20a performs predetermined arithmetic processing on the signal received from the communication unit 21a, or processing such as storing information based on the received signal in the storage unit 22a. Moreover, the process which produces | generates the status information of the sensor 3 or the actuator 4 input from the input / output part 23a, and outputs it to the communication part 21a may be performed.

  The storage unit 22a uses a memory such as a flash memory or a RAM, and stores information received by the arithmetic processing unit 20a via the communication unit 21a or information obtained by arithmetic processing of the arithmetic processing unit 20a.

  The communication unit 21a performs communication processing via the communication line 5 according to a predetermined protocol based on an instruction from the arithmetic processing unit 20a. Processing for converting control information given from the arithmetic processing unit 20a into a signal in a format conforming to the protocol and outputting it, or extracting information from the signal received from the communication line 5 according to the protocol and notifying the arithmetic processing unit 20a Perform processing such as. The communication unit 21a of the input / output device 2a also includes two ports (211a and 212a) as shown in FIG. 2, and distinguishes between communication with the ECU 1 directly connected and communication with the input / output device 2b. Is possible.

  The input / output unit 23a is an interface to which the sensor 3 and the actuator 4 are connected. You may be comprised so that D / A conversion and A / D conversion can be performed. The input / output unit 23a acquires information from the input signal from the sensor 3 and notifies the arithmetic processing unit 20a, or converts the control information from the arithmetic processing unit 20a into a control signal and outputs the control signal to the actuator 4. To do.

  A communication method between the ECU 1 and the input / output devices 2a, 2b, 2c, and 2d configured as described above will be described. In order to perform communication, the ECU 1 as the master identifies the input / output devices 2a, 2b, 2c, and 2d that are the slaves 1 to 4, and the input / output devices 2a, 2b, 2c, and 2d themselves It is necessary to recognize whether it is a destination or not. That is, an address is required as identification information for identifying each. However, as described above, each of the input / output devices 2a, 2b, 2c, and 2d that are the slaves 1 to 4 is not preset with its own address (identification information) for identifying itself. Therefore, as described below, setting is performed by transmitting and receiving information between the ECU 1 as the master and the input / output devices 2a, 2b, 2c, and 2d as the slaves 1 to 4.

  FIG. 3 is a flowchart illustrating an example of an initial setting procedure performed by the ECU 1 serving as a master in the in-vehicle communication system according to the present embodiment. When the control unit 10 of the ECU 1 receives power supply from a power supply device such as a battery or an alternator (not shown) in a state where the input / output devices 2a, 2b, 2c, and 2d are connected via the communication line 5, the initial setting is performed. The following processing is executed as follows.

  The control unit 10 transmits an initial setting frame including address information and data setting information of each slave to one of the adjacent input / output device 2a and input / output device 2b, here, to the input / output device 2a, the port 122 of the communication unit 12. (Step S11). Thereafter, the control unit 10 determines whether or not an initial setting frame transferred from the other adjacent input / output device 2d has been received (step S12). Details of the contents of the initial setting frame will be described later.

  When it is determined that the transferred initial setting frame has not been received from the communication unit 12 (S12: NO), the control unit 10 returns to step S12 and waits until it is determined that it has been received.

  When the control unit 10 determines that the transferred initial setting frame has been received from the communication unit 12 (S12: YES), the input / output devices 2a, 2b, and 2c that are slaves are obtained from the address information of the received initial setting frame. , 2d (step S13). Further, the control unit 10 recognizes areas used for data input / output of each of the slaves 1 to 4 when a data frame for data input / output is transmitted from the data setting information of the received initial setting frame ( In step S14), communication is started in response to recognition of the number of slaves (4) and areas used for data input / output of each of the slaves 1 to 4 (step S15), and the initial setting process is terminated.

  The ECU 1 corresponds to the ring connection of the four input / output devices 2a, 2b, 2c, 2d to which the sensors 3, 3,... And the actuators 4, 4,. Suppose that it is set. As a result, the ECU 1 can confirm whether the set number of slaves matches the number of slaves obtained in step S13. In addition, it is possible to confirm whether the set use area by each of the slaves 1 to 4 matches the use area recognized in step S14.

  FIG. 4 is a flowchart showing an example of an initial setting process performed by the input / output device 2a which is a slave in the in-vehicle communication system according to the present embodiment. Since the processes performed by the other input / output devices 2b, 2c, and 2d are the same, detailed description thereof is omitted.

  When power is supplied from a power supply device such as a battery or an alternator (not shown) while the arithmetic processing unit 20a of the input / output device 2a is ring-connected (daisy chain connected) via the communication line 5 together with the ECU 1, as an initial setting The following processing is executed.

  The arithmetic processing unit 20a determines whether or not an initial setting frame having the ECU 1 as a transmission source has been received from one of the ports 211a and 212a of the communication unit 21a (step S21). If it is determined that the initial setting frame has not been received (S21: NO), the arithmetic processing unit 20a returns the process to step S21 and waits until it is determined that it has been received.

  When the arithmetic processing unit 20a determines that the initial setting frame has been received by the notification from the communication unit 21a (S21: YES), the arithmetic processing unit 20a extracts the address information from the received initial setting frame (step S22). The arithmetic processing unit 20a determines its own address based on the extracted address information (step S23). In the present embodiment, as will be described in detail later, the address information indicates an address value, and the arithmetic processing unit 20a determines the address value indicated by the received address information as its own address. Note that the address determination method is not limited to this, and an address value corresponding to a pre-defined code string indicated by the received address information may be obtained using a table. A result obtained by multiplying “10” may be determined as an address.

  Next, the arithmetic processing unit 20a rewrites the address information of the received initial setting frame based on a predetermined calculation result (step S24). Specifically, the arithmetic processing unit 20a adds “1” to the address value indicated by the address information of the received initial setting frame, and rewrites the address information to indicate the addition result. The value to be added may not be “1”, and is not limited to addition, and may be subtraction, multiplication, division, or a combination thereof. Thereby, when the next input / output device 2b receives the initial setting frame, the address information indicates a value after “1” is added.

  The arithmetic processing unit 20a further writes the setting of data used by itself in the data setting information of the received initial setting frame (step S25). Specifically, the arithmetic processing unit 20a uses the bit string indicating the data setting information of the received initial setting frame for the data input / output by itself from the beginning of the bit string that has not been rewritten by another input / output device. Rewrite as many bits as there are bits. When the next input / output device 2b receives the initial setting frame, the subsequent bit after the bit rewritten by the input / output device 2a is rewritten.

  The arithmetic processing unit 20a transfers the initial setting frame rewritten and written in step S24 and step S25 from the communication unit 21a to the other adjacent input / output device 2b (step S26), and ends the process.

  Since the processing shown in the flowchart of FIG. 4 is also performed in the input / output devices 2b, 2c, and 2d, the initial setting frame rewritten and written by all the input / output devices 2a, 2b, 2c, and 2d Is received by the ECU 1 as a master. As shown in the flowchart of FIG. 3, the control unit 10 of the ECU 1 confirms the number of slaves and all the input / output devices 2a, 2b, 2c, 2d based on the contents of the initial setting frame that has been rewritten and written. The communication can be started after confirming that the communication via the network is normally performed.

  Details of the initial setting frame will be described. FIG. 5 is an explanatory diagram showing an example of the contents of an initial setting frame that repeatedly passes between the ECU 1 and the input / output devices 2a, 2b, 2c, and 2d that constitute the in-vehicle communication system of the present embodiment.

  As shown in FIG. 5, the initial setting frame in this embodiment is composed of 1 byte, that is, 8 address value bits, and 3 bytes, that is, 24 data setting bits. The initial setting frame is transmitted from the ECU 1 as one piece of information.

  Note that, when the initial setting frame in the present embodiment is transmitted from the ECU 1, as shown in FIG. 5, the address value bits are all “0” and the data setting bits are all “1”.

  FIG. 6 is an explanatory diagram schematically showing a situation in which the initial setting frame is transferred between the ECU 1 and the input / output devices 2a, 2b, 2c, and 2d that constitute the in-vehicle communication system of the present embodiment.

  The lower part of FIG. 6 shows the transition of the initial setting frame whose contents change by rewriting and writing.

  Initially, the initial setting frame transmitted from the ECU 1 as the master to the input / output device 2a as the slave 1 has all address value bits “0” and data setting bits “1” as shown in FIG. is there. The arithmetic processing unit 20a of the input / output device 2a, which is the slave 1, reads the address value bit as a numerical value and determines it as its own address. That is, “0000 0000” = “0” is determined as the address. The arithmetic processing unit 20a obtains a numerical value “1” = (0 + 1) obtained by adding “1” to the value indicated by the address value bit, and rewrites the address value bit so as to indicate the numerical value “1”. Furthermore, the arithmetic processing unit 20a specifies the first bit of the bit string that is not rewritten as “1” in the data setting bits. The arithmetic processing unit 20a stores the specified position of the first bit, that is, the “0th bit” in the storage unit 22a. Since the arithmetic processing unit 20a uses 4 bits representing the state information input from the sensor 3 and 2 bits used for the control information of the actuator 4, the bit “0” is added to “6” bits from the identified first bit. Is written. The arithmetic processing unit 20 a transfers the initial setting frame after rewriting and writing to the input / output device 2 b that is the slave 2.

  In the input / output device 2b that is the slave 2, the arithmetic processing unit reads the address value bits as a numerical value. At this time, in the initial setting frame transferred from the input / output device 2a which is the slave 1, the address value bits are rewritten to “0000 0001”. Therefore, the arithmetic processing unit of the input / output device 2b determines “1” as an address, obtains a value “2” = (1 + 1) obtained by adding “1” to the value indicated by the address value bit, and obtains the value “2”. As shown, the address value bits are rewritten to “0000 0010”. Further, the arithmetic processing unit of the input / output device 2b specifies the first bit (“7th bit”) of the bit string that is not rewritten as “1” among the data setting bits, and stores the position of the first bit. deep. Since the arithmetic processing unit of the input / output device 2b uses 4 bits representing the state information input from the sensor 3 and 2 bits and 2 bits used for the control information of the actuators 4 and 4, the specified first bit is used. Write bit “0” into “8” bits. The arithmetic processing unit of the input / output device 2b transfers the initial setting frame after rewriting and writing to the input / output device 2c that is the slave 3.

  Similarly, in the input / output device 2c which is the slave 3, the address is determined to be “2” from the address value bits, and the bit “0” is written in the “5” bits to be used among the data setting bits. Then, the initial setting frame after rewriting and writing is transferred to the input / output device 2 d which is the slave 4. Similarly, in the input / output device 2d that is the slave 4, the address is determined to be “3” from the address value bits, and the bit “0” is written into “5” bits to be used among the data setting bits. Then, the initial setting frame after rewriting and writing is transferred to the ECU 1 which is the master connected in the ring.

  In this case, as shown in FIG. 6, the control unit 10 of the ECU 1 receives from the communication unit 12 an initial setting frame in which the address value bits are “0000 0100” and “0” is written in all the data setting bits. . Thereby, the control part 10 of ECU1 can confirm the number of slaves with "4" from the numerical value = "4" which an address value bit shows. Further, the control unit 10 can confirm whether or not the data setting bit matches a preset use bit and can start communication.

  At this time, the control unit 10 determines that communication cannot be started if the number of slaves and bits used do not match as a result of confirmation, recognizes that the communication is abnormal, and terminates the process. Is also possible.

  When the system is changed, for example, when an input / output device is newly added to the system, an initial setting frame that has already been rewritten and written is transmitted from the ECU 1, and the input / output devices 2a, 2b that have already completed the initial setting , 2c, and 2d are transferred only without rewriting, and the newly added input / output device that has not yet been initialized determines the address and sets the use area from the initial setting frame, and transmits it to the ECU 1. The initial setting frame may be transmitted again as a whole, but by transmitting again the initial setting frame that has already been rewritten and written as described above, the other input / output devices 2a, 2b, 2c and 2d do not change their own address, and do not change the setting of the area of data to be used, and the newly added input / output device performs the setting by itself, and the ECU 1 newly sets If the setting is changed in advance so as to correspond to the added input / output device, communication can be continued.

  FIG. 7 is an explanatory diagram showing a content example of a data frame transmitted and received between the ECU 1 and the input / output devices 2a, 2b, 2c, and 2d in the in-vehicle communication system according to the present embodiment. After the initial setting frame is transmitted and received and the setting process is completed, the ECU 1 transmits a data frame as shown in FIG.

  As shown in FIG. 7, the data frame includes arbitrary identification information indicating that it is a data frame and data bits. In the data bit, data used by each of the input / output devices 2a, 2b, 2c, and 2d is described in combination in bit units.

  Each data bit may be “0” or “1” when it is first transmitted from the ECU 1. The control unit 10 of the ECU 1 may write control information for controlling the actuator 4 of the input / output device 2a in the last two bits of the “6” bit used by the input / output device 2a. When the input / output device 2a first receives a data frame, the position of the first bit of the bit used by itself is read from the storage unit 22a, and the connected sensor is included in 6 bits from the first bit. “1101” indicating the state information input from 3 is written and transferred.

  Similarly, in the input / output devices 2b, 2c, and 2d, since the bits used by the input / output devices 2b, 2c, and 2d are stored in the position of the first bit and the number of bits, the information is read from the bits used or written to the other bits. The data is transferred to the input / output devices 2a, 2b, 2c, 2d and the ECU 1.

  In this way, information used by the plurality of slaves 1 to 4 can be transmitted and received without interfering with each other in one data frame, and communication efficiency is improved. In this case as well, even if a new input / output device is added, the bit used by the new input / output device only needs to be stored by the master ECU 1 and the new input / output device itself. System changes can be handled without changing the settings in the input / output devices 2a, 2b, 2c, and 2d.

  In the present embodiment, the ECU 1 and the input / output devices 2a, 2b, 2c, 2d are ring-connected, and the input / output device 2d transfers the rewritten initial setting frame from a port different from the one that received it. Thus, the initial setting frame could be received by the ECU 1 as the master. However, the present invention is not limited to this. The ECU 1 and the input / output devices 2 a, 2 b, 2 c, 2 d can be realized even when daisy chain connection, that is, when the input / output device 2 d and the ECU 1 are not connected by the communication line 5. In this case, only the input / output device 2d returns from the same port that received the rewritten initial setting frame, and the other input / output devices 2a, 2b, and 2c transmit the initial setting frame from one received to the other in the same manner. This is achieved by performing only transfer.

  In the present embodiment, as described above, the initial setting frame is used, the address information and data setting information including a plurality of bits are transmitted, and the slave performs rewriting to each bit to transfer the information. did. However, the present invention is not limited to this, and the address information and the data setting information may be appropriately transmitted, and the rewriting process may be performed on each. For data setting information, not only rewriting the bits to be used, but also combining the information paired with the identification information of the input / output data so that the master can automatically identify the bits used by each. It may be a thing. In the configuration for rewriting the bits to be used, as described above, in order to recognize which area each slave 1 to 4 uses, it is necessary to set in advance by the master. If it can be automatically specified, it is possible to deal with changes in the system configuration more flexibly.

  The disclosed embodiments should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1 ECU (master communication device)
2a, 2b, 2c, 2d I / O device (slave communication device)
5 communication lines

Claims (7)

In a communication system in which one master communication device and a plurality of slave communication devices communicate by ring connection or daisy chain connection,
The master communication device is
Means for transmitting address information of each slave communication device, and data setting information set to determine data used by each slave communication device;
Means for receiving the address information and data setting information transferred from any of the plurality of slave communication devices,
Each of the plurality of slave communication devices is
Means for receiving the address information and data setting information from one of the adjacent communication devices;
Means for determining and storing its own address based on the received address information;
Means for rewriting the received address information based on a calculation result using the address information;
Means for setting information for determining data used by itself in the received data setting information;
Means for transferring the address information after rewriting and the data setting information after setting to the other of the adjacent communication devices. The master communication device includes means for transmitting a data frame including a plurality of data used by each slave communication device based on the received data setting information,
Each slave communication device receives data from the data frame based on the setting, or transmits data to a corresponding position in the data frame based on the setting. Communication system. In a communication system in which one master communication device and a plurality of slave communication devices are ring-connected or daisy-chain connected to transmit / receive digital signals,
The master communication device is
Means for transmitting a setting signal including an address value bit and a data setting bit each consisting of a plurality of bits;
Means for receiving the setting signal transferred from the slave communication device,
Each of the plurality of slave communication devices is
Means for receiving the setting signal from one of adjacent communication devices;
Means for reading the address value from the address value bits in the received setting signal;
Means for determining and storing an address based on the read address value;
Means for rewriting an address value bit in the received setting signal based on a calculation result of the address value and a predetermined value;
Rewriting means for rewriting one or more bits used by itself among data setting bits of the received setting signal;
And a means for transferring a setting signal including the rewritten address value bit and the data setting bit to the other of the adjacent communication devices. The data setting rewriting means includes
Means for specifying the head position of one or more bits used by itself among the data setting bits of the received setting signal;
Means for storing the identified head position;
4. The communication system according to claim 3, further comprising means for inverting the number of bits used by itself from the stored head position among the data setting bits. The master communication device includes means for transmitting a data signal composed of bits used by each slave communication device based on the received setting signal,
Each slave communication device extracts the bit used by itself based on the stored head position from the data signal, or writes and transmits data from the head position to the bit used by itself. The communication system according to claim 4. In a communication method in which one master communication device and a plurality of slave communication devices communicate by ring connection or daisy chain connection,
The master communication device transmits address information of each slave communication device and data setting information set to determine data used by each slave communication device,
Each of the plurality of slave communication devices is
Receiving the setting information from one of the adjacent communication devices;
Determine your address based on the received address information,
Based on the calculation result using the address information, rewrite the received address information,
In the received data setting information, set information to determine the data used by itself,
Transfer the address information after rewriting and the data setting information after setting to the other of the adjacent communication devices,
The master communication device is
Receiving the address information and data setting information transferred from one of the adjacent slave communication devices;
A communication method characterized by controlling transmission / reception of data by each slave communication device based on received address information and data setting information. In a communication method in which one master communication device and a plurality of slave communication devices transmit and receive digital signals by ring connection or daisy chain connection,
The master communication device transmits a setting signal including an address value bit and a data setting bit each consisting of a plurality of bits,
Each of the plurality of slave communication devices is
Receiving the setting signal from one of the adjacent communication devices;
Read the address value from the address value bits in the received setting signal,
Determine the address based on the read address value,
Based on the calculation result of the address value and the predetermined value, rewrite the address value bit in the received setting signal,
Of the data setting bits of the received setting signal, rewrite one or more bits used by itself,
Transfer the setting signal including the address value bit and the data setting bit after rewriting to the other of the adjacent communication devices,
The master communication device is
Receiving the setting signal transferred from one of the adjacent slave communication devices;
A communication method comprising controlling transmission / reception of data by each slave communication device based on a received setting signal.

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